Research, Teaching, and Political Science

Main menu

Post navigation

Why did Japan surrender in 1945? (War and Peace in East Asia, Lecture 10)

Isolating the causes of Japan’s surrender in August 1945 is a fraught process, because it invokes so many difficult topics, from American firebombing of Japanese cities as soon as its bombers were in range to the nuclear attacks on Hiroshima and Nagasaki to the rapid and brutal Soviet conquest of Manchuria, all framed against Japan’s own atrocities against civilians and soldiers alike in China, its other imperial conquests, and in battles with American forces fighting their way (and mistreating prisoners on their own) towards the Home Islands. Some arguments pride nuclear bombs as the war-ending weapons, some revisionist accounts credit the Soviet invasion of Manchuria, which followed the nuclear attacks and preceded the surrender, but we argued today in class that both claims—often ideological, sometimes for the contrarian or partisan fun of it, and frequently weak on theory—fail to consider a key aspect of the politics of surrender: the personal fates of the top-level civilian and military decision-makers in Japan. Seen in that light, both factors can be seen as necessary components of the surrender.

So we had two questions to answer in class today. First, why did Japan surrender when it did, in August of 1945, despite knowing that the war was as good as lost many months before (after all, its initial gambit based on 50-50 odds of defeating the United States in a short war clearly didn’t pay off)? Second, what ultimately drove it to surrender? As it happens, and as Paine argues pretty convincingly in Chapter 7, Hirohito’s decision to accept the Potsdam Declaration and capitulate (to all the Allies except the Soviet Union, which really did have a lot of trouble convincing people that it was the power least shitty to surrender to) was made possible by both the American attacks on Japanese cities (conventional and nuclear, though the former killed far more in total) and the Soviet destruction of Japanese military might on the Asian mainland.

Paine argues that the first step in this process was the bombing campaign against Japanese cities, capped off with (though not ended by) the nuclear attacks on Hiroshima and Nagasaki, which convinced the civilian leadership that war no longer held out the prospect of survival. But it was the Soviet invasion of Manchuria, which hurled an army of 1.5 million soldiers against a Japanese army starved of resources after years of American submarine attacks against Japan’s merchant marine, that convinced the military of the same. The combination of both events, one imperiling the civilian leadership, the other imperiling the military, was sufficient to prompt the emperor to announce Japan’s acceptance of the Potsdam Declaration—a nominal unconditional surrender that nonetheless left the Emperor’s role intact and, a concern for the army especially, prevented a Soviet occupation of northern Japan. (In fact, Japan’s refusal to surrender to the Soviets has ensured that the latter’s territorial gains at the end of the war—none of which were previously held by the Russian state—remain disputed in a region full of territorial disagreements.)

So which event—the nukes or the Red Army—precipitated the Japanese surrender? From a logical standpoint, it’s impossible to say. Absent a Soviet menace to its position on the Asian mainland, it’s hard to see the army surrendering, especially after it not only refused to do so in the wake of the nuclear attacks but attempted a coup to prevent the civilians from surrendering after Nagasaki. Absent the nuclear attacks, on the other hand, it’s hard to see an otherwise insulated civilian leadership, confident in the army’s ability to bleed the Americans white if they attempted an amphibious invasion of the Home Islands, willing to throw in the towel when the prospect loomed of forcing the Americans into a negotiated settlement after drawing them into the equivalent of many more Okinawas (a seriously costly victory) just to make headway in Operation Downfall, the massive planned operation to invade and complete the conquest of Japan.

Thus, the nuclear attacks, the Red Army, and—of course—Chiang Kai-Shek’s years-long resistance, tying down massive numbers of Japanese troops on the mainland, all contributed to both why and when Japan surrendered. Take away one element, and it’s difficult to see the other two being enough to cause Japan to surrender when and under what terms it did—meaning that the debate over which particular factor was primarily responsible is fairly beside the point.